The purpose of perf_output_{un,}lock() is to:
1) avoid publishing incomplete data
[ possible when publishing a head that is ahead of an entry
that is still being written ]
2) guarantee fwd progress
[ a simple refcount on pending writers doesn't need to drop to
0, making it so would end up implementing something like forced
quiecent states of RCU ]
To satisfy the above without undue complexity it serializes
between CPUs, this means that a pending writer can only be the
same cpu in a nested context, and since (under normal operation)
a cpu always makes progress we're good -- if the head is only
published when the bottom most writer completes.
Now we don't need to disable IRQs in order to serialize between
CPUs, disabling preemption ought to be sufficient, esp since we
already deal with nesting due to NMIs.
This avoids potentially expensive (and needless) local IRQ
disable/enable ops.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1258373161.26714.254.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove fb_save_state() and fb_restore_state operations from frame buffer layer.
They are used only in two drivers:
1. savagefb - and cause bug #11248
2. uvesafb
Usage of these operations is misunderstood in both drivers so kill these
operations, fix the bug #11248 and avoid confusion in the future.
Tested on Savage 3D/MV card and the patch fixes the bug #11248.
The frame buffer layer uses these funtions during switch between graphics
and text mode of the console, but these drivers saves state before
switching of the frame buffer (in the fb_open) and after releasing it (in
the fb_release). This defeats the purpose of these operations.
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11248
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Reported-by: Jochen Hein <jochen@jochen.org>
Tested-by: Jochen Hein <jochen@jochen.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We cannot rely on buffer dirty bits during fsync because pdflush can come
before fsync is called and clear dirty bits without forcing a transaction
commit. What we do is that we track which transaction has last changed
the inode and which transaction last changed allocation and force it to
disk on fsync.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Some drivers need to be able to prevent access to an I2C bus segment
for a specific period of time. Add an interface for them to do so
without twiddling with i2c-core internals.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Conflicts:
tools/perf/Makefile
Merge reason: Resolve the conflict, merge to upstream and merge in
perf fixes so we can add a dependent patch.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf tools: Remove -Wcast-align
perf tools: Fix compatibility with libelf 0.8 and autodetect
perf events: Don't generate events for the idle task when exclude_idle is set
perf events: Fix swevent hrtimer sampling by keeping track of remaining time when enabling/disabling swevent hrtimers
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: Remove cpu arg from the rb_time_stamp() function
tracing: Fix comment typo and documentation example
tracing: Fix trace_seq_printf() return value
tracing: Update *ppos instead of filp->f_pos
Platform drivers registered via platform_driver_probe() can be bound
to devices only once, upon registration, because discard their probe()
routines to save memory. Unbinding the driver through sysfs 'unbind'
leaves the device stranded and confuses users so let's not create
bind and unbind attributes for such drivers.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On UDP sockets, we must call skb_free_datagram() with socket locked,
or risk sk_forward_alloc corruption. This requirement is not respected
in SUNRPC.
Add a convenient helper, skb_free_datagram_locked() and use it in SUNRPC
Reported-by: Francis Moreau <francis.moro@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct sk_buff kmemcheck annotations enlarged this structure by 8/16 bytes
Fix this by moving 'protocol' inside flags1 bitfield,
and queue_mapping inside flags2 bitfield.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-param-fixes:
param: fix setting arrays of bool
param: fix NULL comparison on oom
param: fix lots of bugs with writing charp params from sysfs, by leaking mem.
* 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
HWPOISON: fix invalid page count in printk output
HWPOISON: Allow schedule_on_each_cpu() from keventd
HWPOISON: fix/proc/meminfo alignment
HWPOISON: fix oops on ksm pages
HWPOISON: Fix page count leak in hwpoison late kill in do_swap_page
HWPOISON: return early on non-LRU pages
HWPOISON: Add brief hwpoison description to Documentation
HWPOISON: Clean up PR_MCE_KILL interface
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futex: Move drop_futex_key_refs out of spinlock'ed region
rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang
rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU
rcu: Prevent RCU IPI storms in presence of high call_rcu() load
futex: Check for NULL keys in match_futex
futex: Handle spurious wake up
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Do less agressive buddy clearing
sched: Disable SD_PREFER_LOCAL for MC/CPU domains
The IBM Saturn serial card has only one port. Without that fixup,
the kernel thinks it has two, which confuses userland setup and
admin tools as well.
[akpm@linux-foundation.org: fix pci-ids.h layout]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Michael Reed <mreed10@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
strstrip() can return a modified value of its input argument, when
removing elading whitesapce. So it is surely bug for this function's
return value to be ignored. The caller is probably going to use the
incorrect original pointer.
So mark it __must_check to prevent this frm happening (as it has before).
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When CONFIG_CPU_FREQ is disabled, cpufreq_get() needs a stub. Used by kvm
(although it looks like a bit of the kvm code could be omitted when
CONFIG_CPU_FREQ is disabled).
arch/x86/built-in.o: In function `kvm_arch_init':
(.text+0x10de7): undefined reference to `cpufreq_get'
(Needed in linux-next's KVM tree, but it's correct in 2.6.32).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Tested-by: Eric Paris <eparis@redhat.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
e180a6b775 "param: fix charp parameters set via sysfs" fixed the case
where charp parameters written via sysfs were freed, leaving drivers
accessing random memory.
Unfortunately, storing a flag in the kparam struct was a bad idea: it's
rodata so setting it causes an oops on some archs. But that's not all:
1) module_param_array() on charp doesn't work reliably, since we use an
uninitialized temporary struct kernel_param.
2) there's a fundamental race if a module uses this parameter and then
it's changed: they will still access the old, freed, memory.
The simplest fix (ie. for 2.6.32) is to never free the memory. This
prevents all these problems, at cost of a memory leak. In practice, there
are only 18 places where a charp is writable via sysfs, and all are
root-only writable.
Reported-by: Takashi Iwai <tiwai@suse.de>
Cc: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
